<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
<div>
<h1>注册页面</h1>
  <input type="text" placeholder="请输入用户名" @blur="f()" v-model="user.username">{{info}}<br>
  <input type="text" placeholder="请输入密码" v-model="user.password"><br>
  <input type="text" placeholder="请输入昵称" v-model="user.nickname"><br>
  <input type="button" value="注册" @click="reg()">
</div>
<script src="https://cdn.bootcdn.net/ajax/libs/axios/0.21.1/axios.min.js"></script>
<script src="https://cdn.staticfile.org/vue/2.2.2/vue.min.js"></script>
<script>
    let v = new Vue({
        el:"body>div",
        data:{
          user:{
            username:"",
            password:"",
            nickname:""
          },
            info:""
        },
        methods:{
          reg(){

          },
          f(){
              axios.get("/check?username="+v.user.username)
                  .then(function (response) {
                 v.info = response.data;
              })
            console.log("用户名:"+v.user.username);
          }
        }
    })
</script>
</body>
</html>